Problems of Data Communication and Networking

What is the Data Communication? Data communication meaning is transfer data from one place to another place by using method of computing and communication technologies. Not only can that data move between two or more nodes, without regarding geographical location or technological medium or data content. Data communications incorporates several techniques and technologies as example we can get telecommunications, computer networking and radio/satellite communication. Data communication usually requires communication or transportation medium between the nodes wanting to communicate with each other such as fiber optic cables, copper wire or wireless signals.

What is network? A network meaning is a set of devices connected by communication links. A node can be a PC, printer, or some other device capable of sending and/or receiving data generated by different other nodes on the network. A must network have the capacity to meet a specific number of criteria. The most imperative of these are execution, dependability, and security.

Performance: Performance can be estimated from various perspectives, including transit time and response time. Transit time is the measure of time required for a message to travel from one place to other. Response time is the elapsed time between a request and a reaction. The performance of a system relies upon various variables, including the quantity of clients, the type of transmission medium, the capabilities of the connected hardware, and the efficiency of the software.

Reliability: Network reliability is estimated by the recurrence of failure, the time it takes a connection to recover from failure, and the network’s heartiness in a calamity.

Security: Network security issues include protecting data from unauthorized access, protecting data from damage and development, and implementing policies and From the fault phenomenon, to network diagnostic tools as a means to obtain diagnostic information to determine the Network failure point, find the root cause of the problem, troubleshooting, restore the normal operation of the network. Security issues incorporate shielding information from unapproved get to, shielding data from harm and development, and implementing policies and from fault phenomenon, to network symptomatic devices as a way to get analytic data to decide the System disappointment point, discover the underlying driver of the issue, investigating, reestablish the ordinary task of the system.

Today Organizations and individual users quickly use network techniques and methods for their business purpose. In this environment, network technicians are required to do more than simply add new machines to the network. So technician have to face number of troubleshoot, complex issues and cause. It may be hardware problem, Absence of connectivity, IP Address issues, etc. Technicians should quickly resolve issues as well. With the right tools, problems can be isolated and resolved quickly, returning the network to top-notch performance in no time.

Example of some common Network problems:

• Can’t get an IP address
• Can’t connect to the application server
• Incorrect VLAN assignment
• Duplex mismatch
• Slow Application Performance

The network doesn’t appears. The operating system may alert that an address was not received from the DHCP server. After checking the network adapter status, no address may be configured. There are more causes here, The address doesn’t receive from the DHCP server. The DHCP server may be out of addresses, the server service may be broken, the end device may be configured to use a static address instead of a DHCP address, and also DHCP request from the end device never made it to the server in the first place. This may be the case especially if a new device is configured for a VLAN that is not set up to forward DHCP requests to the DHCP server. Solution As first we must check, How many users are affected? If only one user is affected, check the NIC settings to be sure it is configured to use DHCP. Next, we must check the switch to see which VLAN the port is configured as a member. And also we must Check that other devices on this VLAN can get addresses. If they cannot, the problem may be that the router is not forwarding DHCP requests to the DHCP server. If many users are affected.

The problem is the on the server. The server may not have the DHCP service running, or it may have run out of addresses to distribute. 8 Dead drop Problem Access point, Computer, Phone or Printer connect with wall jack but the connection haven’t for users. Network adapter doesn’t show and switch port hasn’t link light. This is a common problems that call dead drops. It occur when connection is not patched via the wall jack. In many organizations, only those connections that are actively being used are patched. When meeting rooms and offices move to another place time to time then network jacks doesn’t check to new users, or drops that are intentionally left disconnected may not be properly documented. And also some time administrative disable the switch port. Solution: As first, you must check the switch port whether it is activated and that the connection has been properly patched. And also when a devices physically move to the another place such as another office room, be sure to the test new connection and ensure it is working properly.

In this case of an IP Phone, it may be that power is not being sufficiently supplied to the phone. 9 Can’t connect to the application server Problem This can be the case when we using CRM application or email applications. User try to open the application but it may be show the alert that it can’t connect with application server. The common complaint into the help desk is that the network is down, actually this is not the real problem. Several things may be cause this problem. As the key question, we must ask from the user is whether this problem happens continually or only one. If the user’s IP address hasn’t any problem user use proper IP address for the connection, cause may be a routing issue on the network between server and network user. It can be verified with a simple ping. If connectivity is lost sporadically, this can be caused by a busy server that is not responsive to client requests. Solution: After ping test, the cause that routing is not the issue. We must check resources and server load. Does the server run another task such as backup? If this is not the case, you must check the network load between client and server, consider on WAN connections. Frequently, periods of high network system use among customer and server can cause availability issues for the customer.

The most ideal way to do this is by using a SNMP tools. It will utilization over time on these links. And also you must check Ethernet errors on all routers and switches, because packet may be loss between server and client. 10 Poor or bad cable Problem If the client PC is able to link to the network, But performance may be poor. The PC may not be able to connect at all. In the network system today, gigabit is a normal thing for pc. Gigabit requires four set of cable, and also anything lower than Category 5 will not work for Gig. In more established structures this must be consideration. And also any measure of untwisting of the cable (frequently close to the RJ-45 termination or patch panel) can cause the signal broken. This will result in FCS Errors on the switch ports or system connectors. Solution As the most problem with cable issues, the cable essentially should be supplanted. On the off chance that the issue is on the grounds that the link has turned out to be untwisted, replace the cable, you can resolve the problem. When supporting new technologies, for example, Gigabit or Power over Ethernet, the cable must be Cat 5 or better.

DNS problems Problem

The user cannot connect the internet or web applications. The network connection to be down. Domain Name Services might be at fault. The user PC can’t resolve the name of the server with the IP address of that server, so it won’t send an connection request. This is frequently caused by having the wrong DNS server configured on the user, sending DNS asks for that the server does not have in its database, or packet loss on the network system. DNS is a UDP-based protocol, so packet that are lost won’t be retransmitted, problem DNS come fail Solution As first Check the user configuration to see which DNS server it is setup to utilize. Then if it is the wrong server, modify this setting in the user or in the DHCP server which provide it. And also you must test the DNS server from the customer connection over and over to decide whether there is delay accordingly because packet may be lost. And search for Ethernet errors between the customer and server. Catch failing DNS request to decide whether there is any response from the server. Finally setup a tool that will always test the DNS server and give alert when an error happens.

Duplex mismatch Problem

On an Ethernet connection, there are two connected devices operate in different duplex modes. So then with a duplex mismatch, the connection will work, just inadequately. The connection lights will end up dynamic on both the switch and system connector. System execution will perfectly, with throughput dropping to 100Kbps or lower than it. One side of the connection is working in full duplex (transmit and get in the same time) and the other device is working down the middle duplex (transmit OR get at one time). The full duplex side doesn’t need to hold up to transmit, it is configured to transmit whether it is accepting or not. The half-duplex side must hold up until it is not receiving in order to transmit. This means that the full duplex side can interrupt to the half duplex side, causing the half duplex side to prematurely end transmission. If transmission is aborted, the edge will need to be retransmitted.

This will dramatically reduce the bandwidth the half duplex side is able to make use of. Solution In almost all cases, a duplex mismatch is the effect of forcing one side of the connection to full duplex, while leaving the opposite side, the computer, to auto-arrange the connection. The cause is that auto-negotiation will decide the forced full setting and match this configuration. This anyway isn’t the case. The side forced to full duplex is never again sending the proper signaling that auto-negotiation depends on with a specific end goal to decide speed and duplex. The auto-negotiating side of the connecting will be left to speculate the duplex of the connection. If all else fails, auto-negotiating will dependably default to half duplex. This is common duplex mismatch issues happen on the network. To determine this, set all connection on the network to auto-negotiate.

Incorrect VLAN assignment Problem

When putting in new services on the system (remote or VoIP), VLANs are used to confine this traffic from other clients. This requires each switch port supporting these administrations services to be designed for the best possible VLAN. If this doesn’t work The IP phone doesn’t register with the call manager, the PC associated with the telephone will be unable to connect with key servers, or the remote clients may not get proper addressing for the remote environment.

There is a switches are necessary for connecting those designed. Perhaps it was not communicated within the organization to reconfigure certain ports to support new services

Solution

As first you must check the port to confirm which VLANs are supported. Not only that use a VLAN Tag to create VLAN specific traffic to check which VLANs are configured on the port. Check the IP address given by the DHCP server to figure out which VLAN is being given to the port on the off chance that it is untagged. Then again, check the change design to approve the VLAN setup.

Slow application performance Problem

The application is slow down. It may be halt data or freeze loaded screen. The data network connection is blamed for this issue. The server maintenance personal can guess the right place what is the cause of right place. Many issues can make an application slow. Among the most recognized causes are server backups occurring during production hours, and packet loss on the network, slow response from database servers.

According to network technician’s point of view, as first you must find the issue is caused by the server or by the network. To decide this, a catch of use application can be gathered from a customer machine. Search for any retransmissions between the customer and server. There is not a problem transmission, may be packet loss on the network which severely affects application performance. If there are no retransmissions and connectivity between user and server is established, the issue may be in the server and can be monitored from that perspective.

Solution

In spite of the fact that packet analyzers can be exceptionally hard to utilize when finding an issue, they regularly are outfitted with basic counters showing TCP retransmissions. Utilize this counter to help with deciding whether there is packet loss on the system among client and server. Search for Ethernet errors (FCS Errors, Alignment Errors, or Late Collisions) on any switches and routes among client and server that could be causing this packet loss. If there are no mistakes, look packet loss on the WAN on because of excessive utilization across the link connection.

Wireless client can’t connect Problem

The customer can recognize the wireless access point, but it can’t connect with the network. Security credentials, wireless channel interface, and dead spots can cause this issue. Since wireless is undetectable, it can to be extremely hard to track these issues down without an appropriate wireless tool.

Solution

You must use a wireless monitoring tool and measure the signal strength from the issue area, and if possible, conduct a site survey in the area to find for rogue or unknown APs. These might be designed for overlapping wireless channels and can influence known-great clients. Check for noise in the signal from surrounding access points or from noise inducing devices such as microwaves and cordless phones. Monitor the customer as it attempt to access point and look for which step fails –authentication, association, or authorization.

Printing problems Problem

Printing does not reliably work away at the system. A printer may seem available, but print work that are sent to it are not finished. Decide whether just only a single client is encountering this issue or if a few people have a similar issue. If only one user is having the issue, it might be that the PC isn’t mapped correctly to the print server. If this isn’t the reason, the network among client and printer might be to be faulted. Packet loss can cause printing issues, and system availability issues on the printer itself.

Solution

As first Check the printer configuration to ensure it has a good IP address and can access to the print server if it is external to printer. Now and again, refreshing the printer driver has settled printing issues. make sure that activity is getting to and from the printer on the system and that all printer drivers are up to date.